1. Field of the Invention
The present invention relates to a resonant cavity enhanced semiconductor photodetector, and more particularly to such a semiconductor photodetector which exhibits reduced variation in quantum efficiency with wavelength.
2. Background Art
In recent years, as more and more optical transmission systems for optical communications have been designed to operate at ultrahigh speed, there is a need to increase the efficiency and speed of semiconductor photodetectors, which make up the backbone of these optical transmission systems. In order to meet this need, use has been made of resonant cavity enhanced photodiodes (or PDs), in which light is repeatedly reflected to increase the light absorption efficiency (see, e.g., Japanese Laid-Open Patent Publication No. 2001-308368).